1. Technical Field
The invention relates to pendulous accelerometers with electrostatic rebalancing and a method of manufacturing same.
It relates more particularly to pendulous accelerometers of the type comprising a case and a flat pendulum mounted so as to be able to oscillate with respect to the case about an axis of rotation situated in the plane of the pendulum and the distance of which to the center of gravity is small with respect to the size of the pendulum, electrodes supported by a flat surface of the pendulum on each side of the axis being provided for cooperating with electrodes, carried by the case, for creating an electrostatic balancing field.
2. Prior Art
Pendulous accelerometers of the above-defined type are known (Frech Patent 2,509,471) whose pendulum is formed by a disk with substantially parallel conducting flat faces, connected to the case by hinges.
The advantage of a pendulum rotating about an axis close to the center of gravity over a pendulum formed by a disk rotating around an axis situated at the edge, is that the electrostatic forces required for rebalancing the pendulum are smaller. But the manufacturing tolerances mean that it is impossible to make the opposite faces of the pendulum strictly parallel. This lack of parallelism requires either that the air gaps between the electrodes of the pendulum and the electrodes of the case be given a relatively high value, so as to avoid excessive distance discrepancies between the different mutually confronting points or that complex and expensive manufacturing technologies be used. These pendulous accelerometers with slightly off-centered pendulous axis consequently do not constitute an appreciable advance over prior art accelerometers whose pendulum is a disk oscillating around an edge.